Question: Solve for $x$ and $y$ using substitution. ${-2x+y = -11}$ ${x = 4y+2}$
Explanation: Since $x$ has already been solved for, substitute $4y+2$ for $x$ in the first equation. ${-2}{(4y+2)}{+ y = -11}$ Simplify and solve for $y$ $-8y-4 + y = -11$ $-7y-4 = -11$ $-7y-4{+4} = -11{+4}$ $-7y = -7$ $\dfrac{-7y}{{-7}} = \dfrac{-7}{{-7}}$ ${y = 1}$ Now that you know ${y = 1}$ , plug it back into $\thinspace {x = 4y+2}\thinspace$ to find $x$ ${x = 4}{(1)}{ + 2}$ $x = 4 + 2$ ${x = 6}$ You can also plug ${y = 1}$ into $\thinspace {-2x+y = -11}\thinspace$ and get the same answer for $x$ : ${-2x + }{(1)}{= -11}$ ${x = 6}$